お先に[osakini] before
この先の心持ち[konosakinokokoromochi] feelings from this point on
データの先頭[deetanosentou] beginning of data
ペン先[pensaki] pen nibs
一寸先[issunsaki] an inch ahead

一足先[hitoashisaki] one step ahead
烏有先生[uyuusensei] fictitious person
縁先[ensaki] veranda edge
下馬先[gebasaki] dismounting place
火先[hisaki] flames

安全保障条約[anzenhoshoujouyaku] US-Japan Security Treaty
違約[iyaku] breach of contract
違約金[iyakukin] penalty for contract breach
一粒子既約[ichiryuushikiyaku] one particle irreducible (physics)
化学兵器禁止条約[kagakuheikikinshijouyaku] chemical weapons ban treaty

仮条約[karijouyaku] provisional treaty
会う約束[auyakusoku] rendezvous
会員規約[kaiinkiyaku] membership agreement (e.g. for a credit card)
解約[kaiyaku] cancellation of contract
確約[kakuyaku] firm promise